Gearshift device

ABSTRACT

A gear shifting system for idler wheels ( 3 ) comprising sliding sleeves ( 2 ), which are connected torsion-resistant with a main shaft ( 1 ) and can be connected form-locking with an idler wheel ( 3 ) to be shifted via axial displacement. Actuation of the respective sliding sleeve ( 2 ) is provided through at least one adjusting unit ( 4 ), which selects an actuator such that a shifting actuation of the respective sliding sleeve ( 2 ) is possible.

This application is a national stage completion of PCT/EP2003/006882filed Jun. 28, 2003 which claims priority from German Application Ser.No. 102 30 184.0 filed Jul. 5, 2002.

FIELD OF THE INVENTION

The present invention relates to a gear shifting system for idler wheels

BACKGROUND OF THE INVENTION

Gear shifting systems, where shifting occurs by means of axialdisplacement of sliding sleeves, are known from the state of the art.This way, the sliding sleeve concerned can connect an idler wheel to beshifted form-locking with a main shaft. Displacement of the slidingsleeve is accomplished in the familiar gear shifting systems throughshifting elements, such as drivers, shift rails and shift forks. Inorder to accommodate these necessary components in the transmission,additional operations are required on the gearbox housing, which aredisadvantageous.

Among other things, a shifting mechanism in which a threaded spindle isdriven by an electric motor is known from the U.S. Pat. No. 4,498,350publication. An axially displaceable element is provided on the threadedspindle, which is connected via spring elements to a frame, which islikewise axially displaceable by rotating the threaded spindle. Anactuating element is, in turn, provided on the frame, which canselectively engage a first or a second gear wheel with the actuatingelement through the axial displacement of the frame.

This familiar shifting mechanism has a very complicated configuration interms of its constructional layout. Furthermore, a large number ofelements is absolutely required for actuating the one or the other gearwheel.

The present invention is based on the objective of proposing a gearshifting system in accordance with the kind described above, which hasthe lowest possible number of components and nevertheless enables simpleand secure actuation of the gear shifting system.

SUMMARY OF THE INVENTION

Accordingly, a gear shifting system in accordance with the invention isproposed in which the shifting actuation or the adjustment of therespective sliding sleeves is provided by means of at least oneadjusting unit, which actuates an actuator such that a desired shiftingpattern is executed. One adjusting unit or several adjusting units,which are assigned to a sliding sleeve, form a so-called shifting set.

This way, the gear shifting system of the invention enables a shiftingactuation of the respective shifting sleeves without the involvement ofshifting elements, such as drivers, shift rails and shift forks or thelike. This reduces the number of required components significantly,since the gear shifting system in accordance with the invention allowsshifting to be supported without additional actuating devices. Forexample, parallel shifting of the sliding sleeves or gear locking, whichprevents the simultaneous engagement of two gears and a desired gearselection as well as desired shifting patterns can be enabled withlittle effort.

Within the framework of further developing the present invention, it canbe provided that electric motors or the like are used as the adjustingunit. It is also possible that adjusting units driven in a differentfashion are used. As actuators, e.g., pins, slide blocks or the like,can be used, which are provided on the shaft of the adjusting unitpreferably in an eccentric fashion. This way, the gear-maintainingfunction can occur from a circular motion of the shaft in the deadcenters of the shifting path. Also gear switch-off can occur with thehighest gear ratio of the circular motion from the dead centers. Thisway, the highest possible switch-off forces can be realized, which arean essential criterion for evaluating the gear shifting system.

In the gear shifting system of the invention, it can preferably beprovided that several adjusting units are installed for one slidingsleeve, which are arranged preferably offset by about 180° about themain shaft. Other configurations are conceivable as well. For example,additional adjusting units can be used, which then are arranged evenlydistributed across the circumference of the main shaft.

It is especially beneficial if the respective rotational positions ofthe adjusting units or the servo-motors are detected. This way, paralleladjustments of the individual sliding sleeves are also possible.Furthermore, in this way gear recognition and gear securing operationscan be performed. To detect the rotational positions of the shafts ofthe individual adjusting units, a central detection device, for example,or also several detection devices, which are provided in the individualadjusting units, respectively, can be used.

In accordance with a beneficial further development, for example, acentral control unit can be provided. The central control unit canrealize vehicle-coordinated shifting in the gear shifting system inaccordance with the invention. A computer or the like is preferably usedas the central control unit. It is possible that the central controlunit also includes the detecting unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 depicts a sectional view of a gear shifting system in accordancewith the invention;

FIG. 2 depicts a cross-sectional view through a shifting set along thecutting line II—II in accordance with FIG. 1; and

FIG. 3 depicts several enlarged basic representations of a respectiveactuator of an adjusting unit with the second gear engaged, in neutralposition and with the first gear engaged.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a possible configuration of a gear shifting system inaccordance with the invention, wherein only those components that areessential for the invention are described. With respect to the referencenumbers, the same reference number was used for several components ofidentical configuration.

A main shaft 1 of the gear shifting system comprises several axiallydisplaceable sliding sleeves 2, which are seated on the main shaft 1 ina torsion-resistant fashion. By means of axial displacement of therespective sliding sleeves 2, an idler wheels 3, that is supposed to beshifted, can be brought into a form lock with the sliding sleeves 2,wherein the idler wheels 3 are seated rotatably on the main shaft 1 andare engaged with at least one additional torque-transmitting element.

In accordance with the invention, it is provided that the respectivesliding sleeves 2 is actuated by at least one adjusting unit 4. Eachadjusting unit 4 controls an actuator such that a shifting actuation ofthe respective sliding sleeves 2 is enabled.

In the configuration of the gear shifting system proposed here, electricservo-motors are provided as adjusting units 4 for the purpose ofadjusting the sliding sleeves 2, wherein corresponding cable connections7 are provided for the power supply. A pin 5 is provided on the motorshaft 6 as the actuator in an eccentric fashion. The rotary motion ofthe motor shafts 6 is indicated in FIG. 1 by an arrow, respectively. Thepin 5 is arranged in a recess 8 of the respective sliding sleeves 2,wherein the recess 8 is limited by two face sides 9 and 10. This isillustrated in FIG. 3. The pin 5 rests against the two face sides 9 and10. As soon as the motor shaft 6 is rotated with the eccentric pin 5,the corresponding sliding sleeve 2 is displaced axially on the mainshaft 1 so that the sliding sleeve 2 is then engaged form-locking withthe respective idler wheels 3, which is supposed to be shifted.

In a shifting set, the adjusting units 4 are respectively arrangedoffset across the circumference of the main shaft 1, preferably at anangle of 180°, which is evident especially from FIG. 2.

The individual servo-motors of a shifting set, as well as allservo-motors of several shifting sets, are suitably selected by acentral control unit 11. In this embodiment, four shifting sets areprovided, wherein each shifting set comprises two adjusting units 4 onone sliding sleeve 2, respectively.

The central control unit 11 preferably serves for vehicle-coordinatedshifting and is suitably connected to the individual adjusting units 4in terms of technical data transfer. To detect the respective rotationalpositions of the individual servo-motors e.g., each adjusting unit 4 cancomprise a suitable detection device 12, indicated in FIG. 1 as a jaggedarrow. This way a parallel adjustment of the sliding sleeves 2, gearrecognition and also a gear-securing operation can be enabled.

A sectional view of a shifting set is illustrated in FIG. 2. It isapparent from this Figure, as already indicated, that the adjustingunits 4 are arranged offset from the main shaft 4 at an angle of 180°.

FIG. 3 illustrates various rotational positions of a servo-motor withthe pin 5 that is arranged eccentrically on the motor shaft 6. In theupper illustration, a gear, e.g., the second gear, is engaged, whereinin this state the sliding sleeve 2 cannot adjust the eccentricallyarranged pin 5 because the adjusting lever arm is zero. Furthermore, thegear switch-off force is indicated by an arrow in this state.

In the center illustration of FIG. 3, a neutral position is shown, i.e.,in this state no gear is engaged. In the bottom illustration, again ashifted state is indicated, wherein the first gear is engaged.

REFERENCE NUMERALS

-   1 main shaft-   2 liding sleeves-   3 idler wheel-   4 adjusting unit-   5 pin-   6 motor shaft-   7 cable connection-   8 recess-   9, 10 face sides-   11 central unit-   12 detection device

1. A gear shifting system for idler wheels (3), comprising: a pluralityof sliding sleeves (2) torsionally fixed to a main shaft (1) andengaging with the idler wheels (3) to be shifted by axial displacementof the sliding sleeves (2), each sliding sleeve including first andsecond opposing circumferential faces (9,10) parallel to and spacedapart along an axis of rotation of the sliding sleeve; and a pluralityof adjusting units (4) engaging with corresponding sliding sleeves (2),each adjusting unit (4) including a servo-motor having a pin (5) mountedeccentrically on motor shaft (6) and engaging with the first and secondcircumferential faces (9,10) of the sliding sleeve (2) whereby eccentricrotation of the pin (5) with rotation of the motor shaft (6) causesselectable axial movement of the corresponding sliding sleeve (2) andtwo of the plurality of adjusting units (4) engage with each slidingsleeve (2) to facilitate movement thereof.
 2. The gear shifting systemaccording to claim 1, wherein the pin (5) reaches dead center of ashifting path of the sliding sleeve (2) during a circular motion of themotor shaft (6) and the sliding sleeve (2) maintains a form-lockingconnection of one of the idler wheels (3) to be shifted in the deadcenter.
 3. The gear shifting system according to claim 1, wherein thetwo of the plurality of adjusting units (4) engaging each of the slidingsleeves (2), are arranged offset about the main shaft (1) at an angle ofabout 180° with respect to one another.
 4. The gear shifting systemaccording to claim 1, wherein a central control unit (11) is providedfor a vehicle-coordinated shifting operation.
 5. The gear shiftingsystem according to claim 1, wherein at least one detection device (12)is provided for detecting rotational positions of the motor shaft (6) ofeach adjusting unit (4) of the plurality of adjusting units (4).
 6. Thegear shifting system according to claim 5, wherein the detection device(12) is integrated into each of the plurality of adjusting units (4). 7.A gear shifting system for idler wheels (3), comprising: a plurality ofsliding sleeves (2), each sliding sleeve (2) being torsionally fixed toa main shaft (1) and engaging with at least one idler wheel (3) to beshifted by means of axial displacement of the sliding sleeve (2); eachsliding sleeve including a circumferential recess (8) having first andsecond opposing face sides (9, 10) parallel to and spaced apart along anaxis of rotation of the sliding sleeve; a plurality of adjusting units(4), two or more of the plurality of adjusting units (4) engaging with acorresponding sliding sleeve to selectively axially displace thecorresponding sliding sleeve (2) along the main shaft (1) and includinga servo-motor having a motor shaft (6) rotating about an axisperpendicular to an axis of the main shaft, and each of the adjustingunits (4) having a pin (5) mounted eccentrically on the motor shaft (6)to have an axial movement along the axis of the main shaft as the motorshaft (6) rotates and engaged with the recess (8) of the correspondingsliding sleeve (2) whereby eccentric rotation of the pin (5) causesselectable axial displacement of the corresponding sliding sleeve (2).